N.1
9 = 1 + 8 × 1
98 = 2 + 8 × 12
987 = 3 + 8 × 123
9876 = 4 + 8 × 1234
98765 = 5 + 8 × 12345
987654 = 6 + 8 × 123456
9876543 = 7 + 8 × 1234567
98765432 = 8 + 8 × 12345678
987654321 = 8 + 8 × 123456789
N.2
11 = 2 + 9 × 1
111 = 3 + 9 × 12
1111 = 4 + 9 × 123
11111 = 5 + 9 × 1234
111111 = 6 + 9 × 12345
1111111 = 7 + 9 × 123456
11111111 = 8 + 9 × 1234567
111111111 = 9 + 9 × 12345678
N.3
88 = 7 + 9 × 9
888 = 6 + 9 × 98
8888 = 5 + 9 × 987
88888 = 4 + 9 × 9876
888888 = 3 + 9 × 98765
8888888 = 2 + 9 × 987654
88888888 = 1 + 9 × 9876543
888888888 = 0 + 9 × 98765432
9 = 1 + 8 × 1
98 = 2 + 8 × 12
987 = 3 + 8 × 123
9876 = 4 + 8 × 1234
98765 = 5 + 8 × 12345
987654 = 6 + 8 × 123456
9876543 = 7 + 8 × 1234567
98765432 = 8 + 8 × 12345678
987654321 = 8 + 8 × 123456789
N.2
11 = 2 + 9 × 1
111 = 3 + 9 × 12
1111 = 4 + 9 × 123
11111 = 5 + 9 × 1234
111111 = 6 + 9 × 12345
1111111 = 7 + 9 × 123456
11111111 = 8 + 9 × 1234567
111111111 = 9 + 9 × 12345678
N.3
88 = 7 + 9 × 9
888 = 6 + 9 × 98
8888 = 5 + 9 × 987
88888 = 4 + 9 × 9876
888888 = 3 + 9 × 98765
8888888 = 2 + 9 × 987654
88888888 = 1 + 9 × 9876543
888888888 = 0 + 9 × 98765432